The present invention relates to a damper (shock absorber) intended for vehicles which is arranged with selectable or adjustable damping force characteristics that are essentially independent of other internal or external function factors in the damper. It relates primarily to vehicles in the form of cars, motorcycles, snow-scooters, etc, where the damper is arranged between movable parts comprised in the vehicle, for example between wheels, runners, etc, and a chassis.
Dampers of this kind are found in large numbers and reference can be made, for example, to shock absorbers that are sold by the applicant making the present patent application. Reference is also made to patents that have been obtained by the applicant and to patent applications previously submitted by the applicant within this field.
With this kind of damper, there is a desire for the damper's functional and/or handling characteristics to be able to be improved and made more clear-cut and yet still be able to have a simplified and less bulky construction. The object of the invention is, among other things, to solve all or parts of this problem.
There is also a need for the damper's damping force characteristics to be able to be made more clear-cut and for set or selected damping characteristics to be able to be selected when assembling dampers and when making adjustments, without at the same time affecting any other function or functions in the damper. Thus, for example, in an embodiment, the damping force characteristics must be able to be set without, for example cavitation arising or being increased or reduced. The damper's fixing must also be able to be made more clear-cut and compact constructions must be able to be arranged. Hysteresis and so-called “flex” must be able to be essentially minimized. Where a compressible medium is utilized to pressurize the damper, it is important that the gas volumes are kept to a minimal level. The pressurizing by means of the compressible medium or corresponding function (for example a spring function) is in order to increase the viscosity of the oil or fluid and to reduce the risk of cavitation. In addition to the ability to reduce the size of the damper as such while retaining good functionality, there is a desire to achieve effective cooling of the medium or mediums used in the damper. It is also important to ensure good and economically advantageous sealing and/or guiding functions that produce relatively small frictional forces on the piston rod or on the piston rod elements during their movements in the damper. Thus, for example, there is a desire to minimize the friction on the piston rod or the piston rod elements by using the least possible number of seals and/or bushings for guiding the piston rod in the cylinder barrel and through the end walls of the cylinder barrel or the like. Thus, for example, it must be possible to use a floating seal and to reduce the dimension tolerances of the cylinder barrel. The volume of the damper medium or mediums must be able to be kept within a certain range, in order to ensure the function of the damper. In a preferred embodiment, in a damper utilizing a separating piston, it must be possible to read off or determine the position of the separating piston. This must be able to be carried out without, for example, having to dismantle all or parts of the damper. An end eye utilized as a fixing device must, in addition, be able to be arranged in such a way that no resulting force will arise on the piston rod as a result of the internal overpressure that is caused by the compression of the medium concerned. There can also be difficulties in determining whether the damper is pressurized or not. There are also problems in being able to ensure that a separating piston that is utilized is in the correct position when the damper is filled with the medium. A relatively large amount of work has previously been required in order to ensure this and there is a desire to be able to reduce this work. It is also important to be able to prevent the damper medium leaking out as a result of a separating piston that is utilized leaving its sealed course during the filling. When a pressure indicator is utilized to check the quantity of damper medium, there is a need for simple pressure indication functions that are easy to use but that are still clear-cut in their function. Among other things, it is important that the connection hole or holes for the pressure indictors can be made relatively small. There is also a desire for the seal(s)/bushing(s) to be located as close to the main piston as possible, in order to minimize the length of the piston rod arrangement and thereby minimize the total length of the damper, without increasing the cost of production. Where a top eye is utilized, it must be able to be mounted at any angle to the body of the damper in a simple way, without the locking of the top eye encroaching upon the length of the damper The object of the invention is also to solve all or parts of these additional problems.